(a) Field of the Invention
The present invention relates to an improved electrical heating device securable to a mirror rear coated surface to heat the mirror to a temperature exceeding the ambient temperature of the mirror when used in an area where there is water vapour in the air so that there is no condensation on the mirror.
(b) Description of Prior Art
It is known to increase the temperature of a mirror above that of the ambient temperature so that condensation does not occur on the surface. This is done in the prior art by circulating hot water against the rear surface of the mirror, as disclosed in U.S. Pat. No. 4,558,929, for example, or by applying a current across a resistive film to defrost the mirror such as described in U.S. Pat. Nos. 3,686,473 or 3,530,275.